The present invention relates to a semiconductor device and a method for manufacturing the same, and more particularly, to a semiconductor device that accomplishes contact stabilization between contact plugs and bit lines and a method for manufacturing the same.
As the design rules of semiconductor devices decrease, the height of capacitors in the semiconductor devices gradually increase in order to sufficiently secure the capacitance of a DRAM (dynamic random access memory).
In a DRAM having a COB (capacitor-over-bit line) structure, as the height of a capacitor gradually increases, the aspect ratio of metal contact plugs, which are formed on bit lines in the core region and the peripheral region of a semiconductor substrate, increases. The increase in the aspect ratio of the metal contact plugs decreases the overlap margin between the metal contact plugs and the bit lines. As a consequence, the metal contact plugs and the bit lines in the core region and the peripheral region of the semiconductor device are likely to be misaligned.
FIG. 1 is a cross-sectional view showing the misalignment between a metal contact plug 162 and a bit line 132 when the metal contact plug 162 is formed in a core region or a peripheral region according to the conventional art.
The reference numeral 100 designates a semiconductor substrate, 110 a gate, 111 a junction area, 113 spacers, and 172 a metal line.
Due to the high integration of a semiconductor device, the misalignment between the bit line 132 and the metal contact plug 162 can cause a short circuit between the gate 110 and the junction area 111, and thereby, the operation characteristics of the semiconductor device are deteriorated.
For example, the high integration of the semiconductor device decreases the overlap margin between the metal contact plug 162 and the bit line 132 in the core region and the peripheral region. The decreased overlap margin may result in the misalignment between the bit line 132 and the metal contact plug 162. As a consequence, an undesirable short circuit can be formed which results in the deterioration of the operation characteristics of the semiconductor device.